The range of healthy body weights is calculated based on BMI. Given a specific height, the calculator uses standard algorithms to calculate the range of possible body weights that fall within different categories of weight determined by BMI. An adult aged 18 or older with a BMI between 18.5 and 25 kg/m2 is typically defined as having a healthy or normal weight. Refer to the BMI Calculator for more information, but note that a "healthy body weight" is based on estimations that do not account for certain factors such as body composition. While accurate for an "average" person, this means that it is possible to be categorized as overweight or underweight and still be "healthy," but this requires more than a generalized calculation to determine – likely with the help of a medical professional.